SSM perspective
Background
The Swedish Radiation Safety Authority’s (SSM) Scientific Council on Electromagnetic Fields monitors current research on potential health risks with a correlation to exposure to electromagnetic fields and provides the Authority with advice on assessing possible health risks. The Council gives guidance when the Authority must give an opinion on policy matters when scientific testing is necessary. The Council is required to submit a written report each year on the current research and knowledge situation.
This is a consensus report. This means that all members of the Scientific Council agree with the complete report. This increases the strength of the given conclusions.
Objective
The report has the objective of covering the previous year’s research in the area of electromagnetic fields (EMF) and health. The report gives the Swedish Radiation Safety Authority an overview and provides an important basis for risk assessment.
Results
The present report is number thirteen in a series and covers studies published from April 2017 up to and including March 2018. The report covers different areas of EMF (static, low frequency, intermediate, and radio frequency fields) and different types of studies such as biological, human and epidemiological studies.
No new causal relationship between EMF exposure and health risks have been established.
Overall, the age standardised incidence of brain tumours is within the annual variations which can be statistically expected and do not give support to any causal relationship with radio wave exposure from mobile phone use.
The majority of the animal studies carried out on oxidative stress have indicated a possible relationship with radio wave exposure, some even below reference levels. The results are however not an established effect and further studies are needed to confirm the association in animals and to establish whether, and to what extent, it may occur in humans. Oxidative stress is a natural biological process that can sometimes be involved in pathogenesis, but under what circumstances needs to be investigated.
Two large animal studies (the US National Toxicology Program (NTP) study and the Italian Falcioni et al. study) have been published during the period. Both studies observed a relationship between radio wave exposure and Schwannoma in the heart for male rats. There is some inconsistency in the results between the two studies which weakens the significance of the results. Even if radio wave exposure could induce Schwannoma in the heart in humans, it is a very rare tumour in humans and therefore, the relevance for public health is most likely low.
MRI workers are exposed to strong static magnetic fields. New epidemiological studies on MRI-exposed workers suggest increased risks of menometrorrhagia (excessive uterine bleeding, both at the usual time of menstrual periods and at other irregular intervals) in women using intrauterine devices, accidents during commuting and high blood pressure. Underlying mechanisms are unclear. Future studies should explore if these associations are true or if alternative explanations such as residual confounding, i.e. other factors related to MRI work and the outcomes under investigations, underlie the observed associations.
The annual report also has a section covering other relevant scientific reports published recently.
Many studies have been excluded due to poor quality. From a scientific perspective, studies of poor quality are irrelevant. They are also a waste of money, human resources and, in many cases, experimental animals
Relevance
The results of the research review give no reason to change any reference levels or recommendations in the field.
The hands-free recommendation for mobile phone calls remains even though trends of glioma incidences do not provide support for an increasing risk caused by mobile phone exposure. However, uncertainties regarding possible long-term effects justifies caution.
The authorities’ recommendation to limit the exposure for low frequency magnetic fields still remains, due to the conceivable correlation between this kind of fields and childhood leukemia.
Need for further research
Despite the fact that no health risks with weak electromagnetic fields have been established today, the Authority considers that further research is important especially regarding long-term effects especially as the entire population is exposed. One key issue here is to further investigate the possible relationship between radio wave exposure and oxidative stress. Another vital issue is to clarify the association between weak low frequency magnetic fields and childhood leukemia as observed in epidemiological studies.
New technology for inductive wireless energy transfer based on intermediate frequency magnetic fields will probably be implemented for many different applications in the near future. In contrast to wireless information transfer technology, wireless energy transmission in principle always requires relatively strong local fields. This makes it very important to obtain a robust basis for risk assessment of such fields. Today there is a lack of studies in this frequency domain, therefore there is a special need for research here.